In the particular field of gardening extensible hoses for irrigation are known that offer the advantage of being able to reduce their bulk when they are not used. A hose of this type is normally made from an elastically stretchable material—for example natural or synthetic rubber, thermoplastic rubber (TPR)—which, under the action of the pressure of the fluid that flows through it, increases its length in use even by tens of times, as well as expanding in diameter.
This phenomenon thus allows for an irrigation hose having a length such as to satisfy the most common requirements of use, but that at the same time, when stowed or not used, has a much smaller bulk with respect conventional hoses.
In this condition, therefore, the hose can, for example, be easily transported; moreover, once the irrigation operation has ended, the hose can be particularly quickly and easily wound back up, to be able to then be stowed away.
One of the critical factors in the use of this type of hose is of course the resistance to perforation and/or laceration and/or to other external agents of the material used.
Indeed, in order to be able to ensure the necessary requirements of protection against such external agents, often in the design of these hoses the thickness of the hose is oversized.
This translates into an increase in the raw materials used, and therefore in the production costs of the object, as well as into an increase in the weight of the hose itself.
Moreover, the increase in thickness of the hose obviously also has an impact on the elastic properties thereof: as can be imagined, for the same pressure of the fluid, an increase in thickness results in a reduction of the stretching able to be obtained in the hose.
Therefore, the advantages that can be obtained thanks to the extensibility of the hose are substantially reduced where it is necessary to pay special attention, in the the design step, to the resistance of the hose itself to external agents.
Up to now various constructive solutions for this type of hose have been proposed, but none of them is considered particularly satisfactory in terms of the elongation that can be obtained and, jointly, that of the resistance to external agents.
For example, solutions have been devised in which the extensible hose is covered with a sheath made from fabric or another similar material.
Such a sheath is unable to provide sufficient guarantees in terms of resistance to external agents, and also tends to collect dirt and also to become impregnated with liquid possibly present on the ground on which it operates.